AR Gas Systems

Alright, I have three basic choices for an AR upper. Short (or Carbine Length), Mid-Lenght, and Rifle Length. As I understand it, the short lenght produces more gas pressure and thus more wear and tear on the weapon than the other lenghts. Can someone explain this better?

i'm no rocket scientist (i just shoot the things), but offhand i'd say that the gas "system" is pressurized from the time the bullet passes the port until the bullet leaves the barrel, right?

so it stands to reason that the closer the gas port is to the receiver, (and given a standard 16" length barrel), the more gas you get.

now, on top of that, i believe a carbine length gas system with a short barrel still gives you more gas than a rifle length with a longer barrel, but i'm not exactly sure why

Avenger29

November 11, 2006, 07:09 PM

Still looking for a little more detail. I have read on this board that a rifle length produces 15,000 PSI compared to the carbine's 30,000 PSI. That is a big difference between lenghts. I really want to know if this has effect on the life expectancy of parts.

dispatch55126

November 11, 2006, 07:28 PM

The differance in pressures is due to the same volume of gas contained within a smaller (carbine) or larger (rifle) container (gas tube). I don't know the details as far as whether the parts are interchangable or if carbine parts are made to handle the increase in pressures.

Critter183

November 11, 2006, 07:53 PM

I've never heard anything about short barrels wearing out bolts faster than long barrels. I have two 16 inchers and one 24 incher, and they all seen plenty of rounds go through them. I notice no excessive wear on any of the bolts.

Critter183

November 11, 2006, 07:56 PM

I don't know the details as far as whether the parts are interchangable or if carbine parts are made to handle the increase in pressures.

I mix and match and swap around parts all the time. There's no difference in parts at all.

I have hung around AR15.Com on and off over the last 6 or 7 years and I never once saw this topic come up. I would think that if there was a major increase in wear rates, someone would have spoken of it at some point.